Firing device for limpet mine

ABSTRACT

1. An anti-removal device for an underwater demolition weapon comprising, A SPRING-BIASED PLUNGER IN SAID WEAPON ADAPTED FOR CONTACTING THE SURFACE OF THE TARGET WHEN THE WEAPON IS ATTACHED THERETO, A DETONATOR FOR DETONATING THE MAIN CHARGE OF THE WEAPON, A SPRING ACTUATED FIRING PIN FOR STRIKING SAID DETONATOR, SAFETY MEANS RELEASABLY ENGAGING SAID FIRING PIN FOR NORMALLY HOLDING SAID PIN IN A RETRACTED POSITION, A TIMING MECHANISM, AND MEANS ACTUATED BY SAID TIMING MECHANISM AFTER A PREDETERMINED PERIOD OF TIME HAS ELAPSED FOR PHYSICALLY CONNECTING SAID SAFETY MEANS AND SAID PLUNGER, WHEREBY THE SUBSEQUENT MOVEMENT OF SAID PLUNGER IN EITHER DIRECTION CAUSED BY ANY ATTEMPT TO REMOVE OR TAMPER WITH THE WEAPON WILL CAUSE THE PLUNGER TO RELEASE SAID SAFETY MEANS AND THEREBY DETONATE THE MAIN CHARGE.

Bayer et al.

[451 May 29, 1973 i 1 FIRING DEVICE FOR LIMPET MINE [75] Inventors: Theodore H. Bayer, Dover Plains; David W. Beaman; Dell K. Tower, both of Poughkeepsie, all of NY.

[73] Assignee: The United States of America as represented by the Secretary of the Navy, Washington, DC.

[22] Filed: June 15, 1964 [21] Appl. No.: 376,300

[52] U.S. Cl ..102/l6, 102/10 [51 Int. Cl. ..F42c 15/10 [58] Field of Search ..102/7, 8, 10, 16, 102/17, 70, 71, 76, 82-84 [56] References Cited UNITED STATES PATENTS 2,514,999 7/1950 Kharasch et a] ..102/84 3,030,887 4/1962 Simmen et al ..l02/84 Primary ExaminerVerlin R. Pendegrass AttorneyJ. P. Dunlavey and J. O. Tresansky EXEMPLARY CLAIM 1. An anti-removal device for an underwater demolition weapon comprising,

a spring-biased plunger in said weapon adapted for contacting the surface of the target when the weapon is attached thereto,

a detonator for detonating the main charge of the weapon,

a spring actuated firing pin for striking said detonasafety means releasably engaging said firing pin for normally holding said pin in a retracted position,

a timing mechanism,

and means actuated by said timing mechanism after a predetermined period of time has elapsed for physically connecting said safety means and said plunger,

whereby the subsequent movement of said plunger in either direction caused by any attempt to remove or tamper with the weapon will cause the plunger to release said safety means and thereby detonate the main charge.

5 Claims, 6 Drawing Figures Llllll'lTTm I4 I! i ll qoi '5 I 37 ll I I 32 Q". i 34 ll! 1 PATENTEU 3, 735, 703

SHEET 1 BF 3 INVENTORS 33 35 36 Theodore H. Bayer, David w Beamon, DeH K. Tower AGENT.

PATENI W 2 91975 SHEET 2 OF 3 Mg;egg h ..l m Wigwam? l FIG. 3

INVENTORS Theodore H. Bayer, David W. Beaman, De K. Tower l- ATTORNEY Pmimwz 3'. 735.703

SHEET 3 OF 3 SAFE ARMED CONDITION FIG. 6

INVENTORS Theodore H. Boyer, David W. Beamon, De" K. Tower BY W ATTORNEY AGENT FIRING DEVICE FOR LIMPET MINE The present invention relates to an anti-removal device for use with an underwater demolition weapon or limpet adapted to be attached to the outer surface of the hull of a ship, and more particularly to an arming and firing mechanism for preventing removal of the limpet from the target without detonating the explosive charge within the limpet.

In certain areas of underwater warfare persons have been equipped for extended periods of underwater swimming and charged with the mission of military reconnaissance and demolition of underwater obstacles. One of the major objectives of these swimmers, who have become widely referred to as frogmen, is that of attaching to the exterior hull of a ship or other target an explosive charge having an automatic firing mechanism equipped with a suitable time delay device for detonating the charge a predetermined period of time after it has been attached to the target and armed. If these limpet weapons are discovered in time by the personnel aboard the target ship, it has been possible in the past to remove them or otherwise render them ineffective before the time delay period has elapsed, to thereby prevent the successful accomplishment of the frogmans ultimate mission of destruction. For these reasons devices have been incorporated into the limpet weapons for the purpose of preventing the removal or tampering with the limpet, but these devices have not proved entirely satisfactory because they were not found to be positively effective for their intended purposes.

Therefore, it is an object of the present invention to provide a new and improved arming and firing mechanism for a limpet weapon having positive means for preventing removal of or tampering with the limpet without detonating the charge.

Another object of the present invention is to provide a new and improved arming and firing mechanism for a limpet weapon which combines numerous safety features for protecting the handler attaching the limpet to the target with a means for positively preventing removal or tampering with the limpet.

Another object of the present invention is to provide a novel and improved anti-removal device for detonating the explosive charge in a limpet weapon when any attempt is made to remove the limpet from its target.

Still other objects and features of the invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings in which like reference numerals designate like parts throughout the figures thereof and wherein:

FIG. 1 is a top plan view of the anti-removal demolition firing device with certain parts broken away;

FIG. 2 is a transverse sectional view taken along line 2-2 of FIG. 1;

FIG. 3 is a transverse sectional view taken along line 3-3 of FIG. 1;

FIG. 4 is a fragmentary view of the timer mechanism, the shutter, the sensing plunger and the associated moving parts of the device;

FIG. 5 is a view similar to FIG. 4 showing the device in the safe condition; and

FIG. 6 is a fragmentary view similar to FIG. 5 showing the device in the armed condition.

Referring now to the figures in detail, the antiremoval device of the present invention consists essen-;

tially of three major elements and their associated components, generally shown as a base block'lO, a firing pin block 11 and a timer mechanism 12. In its shipping state the unique design of the device incorporates a variety of structural features for preventing any accidental firing during the transportation and handling of the device. These features include a positive block on the firing pin 13 afforded by a latch l4-which is held in place by a safety screw pin 15 threaded into the firing pin block 11. In addition to the aforementioned positive block, there is also a physical block maintained between the firing pin 13 and the explosive detonator 16 in the form of a shutter member 17 which is locked in position by the interaction of an arm 18 and a push rod 19. Shutter 17 blocks the firing pin 13 even though the safety screw pin 15 is removed before the timer mechanism 12 is wound, and it cannot be moved from its safe" position nor can the push rod 19 be depressed until the timer mechanism is wound. A-wire 41 is shown wound about the screw pin 15 and the push rod 19 and is provided for the purpose of carrying a safety tag warning personnel against removing the screw pin 15 if the shutter 17 is not so positioned that it will block the firing pin 13.

Another safety feature of the device is that it cannot be inserted into the limpet weapon until the clockwork has been fully wound and the safety screw pin 15 has been removed. This insures the full time delay to occur and is accomplished by the interlocking relationship of the push rod 19 and the timing mechanism arm 18. Moreover, the time delay arming feature does not begin its cycle until an arming wire 20 is removed, releasing the sensing plunger 21 of the device. Should this wire 20 be removed by accident before the charge is placed, the timing cycle is arrested and the arming wire may be replaced.

To prepare the device for service the timer mechanism 12 is fully wound and the safety screw pin 15 is removed. Winding the timer mechanism moves the shutter 17 and arm 18 so that the operation of the push rod 19 is not blocked, and it thereafter is forced outward by spring 22. The firing device then can be inserted into the limpet weapon, which it is to be understood is properly dimensioned to depress the push rod 19 to a position allowing operation of the timing mechanism. The timing mechanism 12, however, will not run because the stop pin 23 engages and interferes with a gear 24 in the mechanism. A projection 25 on the sensing plunger 21 working against lever 26 holds the stop pin 23 in engagement with the clockwork of the timer mechanism.

When the limpet is placed on the target, the'arming wire 20 is removed, allowing the sensing plunger 21 driven by spring 27 to extend and contact the surface of the target. Movement of the sensing plunger 21 allows a stop pin spring member 28 to withdraw the stop pin 23 from the gear 24 of the timing mechanism, thus beginning the time delay of a predetermined period of time. However, if the plunger 21 should move outward so far that the projection 29 on the side thereof engages a lower lever 30, the stop pin 23 will again be placed in a position where it will arrest movement of the timing mechanism. This indicates that an improper placement of the limpet has been made and allows the user to attempt a replacement merely by reestablishing the plunger in its locked" position and replacing the arming wire 20, as hereinbefore described, or if left in this position prevents the timing cycle from being completed and the charge within the limpet from automatically firing.

At the completion of the arming period, the timing mechanism 12 through the finger extension 31 on the shutter 17 releases a cam latch 32 and allows the shaft 33 to move forward under the force of a spring 34 from the safe condition shown in FIG. to the armed" condition shown in FIG. 6 wherein a projection 36 on hub portion 35 of shaft 33 engages the plunger 21. The edge of the projection 36 is sharp and hard and becomes slightly embedded in the sensing plunger 21 as a result of the impact. It will be observed that the firing pin 13 is still held on the latch 14 by means of an upward extending finger 37 on the hub 35. Any subsequent axial movement of the plunger 21 in either direction will cause the hub 35 to rotate on shaft 33 until the uppermost finger 37 releases the latch 14. When this occurs, the firing pin 13 is driven by spring 38 into the explosive detonator l6 housed in a threaded holder 39, to subsequently detonate the main charge in the limpet.

It should be apparent that the novel device provided by the present invention is such that it will be difficult to develop a procedure for defeating the limpet equipped with the device. Once the limpet has been attached to the target by any suitable means and appropriately armed, the sensing plunger will contact the target and any attempt to remove the limpet or tamper with it causing axial movement of the plunger in either direction will result in the immediate detonation of the limpet main charge. It should be further appreciated that not only does the present invention provide a positive anti-removal device for a limpet weapon, but the unique design of the device further affords numerous and unusual safety features.

While the invention as been described in detail with respect to a specific embodiment of this invention, it is to be understood that the invention is not to be limited thereto but may be embodied in various forms without departing from the spirit of the invention as defined by the appended claims.

What is claimed is:

1. An anti-removal device for an underwater demolition weapon comprising,

a spring-biased plunger in said weapon adapted for contacting the surface of the target when the weapon is attached thereto,

a detonator for detonating the main charge of the weapon,

a spring actuated firing pin for striking said detonator,

safety means releasably engaging said firing pin for normally holding said pin in a retracted position,

a timing mechanism,

and means actuated by said timing mechanism after a predetermined period of time has elapsed for physically connecting said safety means and said plunger,

whereby the subsequent movement of said plunger in either direction caused by any attempt to remove or tamper with the weapon will cause the plunger to release said safety means and thereby detonate the main charge.

2. An anti-removal device for an underwater demolition weapon comprising,

a spring-biased plunger in said weapon for contacting the surface of the target when the weapon is attached thereto,

a detonator for detonating the main charge of said weapon,

a spring actuated firing pin for striking said detonator,

lever means releasably engaging said firing pin for normally holding said pin in a retracted position,

a spring actuated shaft having a hub portion rotatably mounted thereon,

said hub portion having a finger-like extension thereon normally contacting said lever means to maintain said lever means engaged with said firing pm,

said hub portion further having a sharp-edged projection thereon radially displaced from said finger extension,

a timing mechanism,

and means actuated by said timer mechanism after a predetermined period of time has elapsed for releasing said spring actuated shaft whereby said shaft moves past said plunger and said sharp-edged projection becomes embedded in said plunger,

whereby any subsequent movement of said plunger in either direction caused by an attempt to remove the weapon from the target will cause the plunger to rotate the hub portion and finger extension thereon to release said lever means and thereby detonate the weapon.

3. Apparatus according to claim 2 wherein said timer mechanism actuated means includes a shutter element physically positioned between said firing pin and said detonator during the transporting and handling of the weapon and adapted to be displaced from that position when the timer mechanism is fully wound to arm the device,

said shutter having an integral segment extending therefrom for releasing said spring actuated shaft at the end of the arming period.

4. Apparatus according to claim 2 and further including means for arresting the movement of the timing mechanism if said plunger is permitted to move more than a predetermined distance when actuated to contact the surface of the target,

whereby if an improper placement of the weapon is made or if the plunger is actuated accidentally during handling, the timing cycle will be prevented from being completed and the weapon will not automatically fire.

5. An anti-removal device for a limpet weapon comprising,

a spring biased plunger in said weapon for contacting the surface of the target when the weapon is attached thereto and suitably armed,

a detonator for detonating the main charge of the weapon,

a spring actuated firing pin for striking said detonator,

and means responsive to movement in either direction of said armed plunger for releasing said firing pin to detonate the limpet weapon.

# Ill t i 

1. An anti-removal device for an underwater demolition weapon comprising, a spring-biased plunger in said weapon adapted for contacting the surface of the target when the weapon is attached thereto, a detonator for detonating the main charge of the weapon, a spring actuated firing pin for striking said detonator, safety means releasably engaging said firing pin for normally holding said pin in a retracted position, a timing mechanism, and means actuated by said timing mechanism after a predetermined period of time has elapsed for physically connecting said safety means and said plunger, whereby the subsequent movement of said plunger in either direction caused by any attempt to remove or tamper with the weapon will cause the plunger to release said safety means and thereby detonate the main charge.
 2. An anti-removal device for an underwater demolition weapon comprising, a spring-biased plunger in said weapon for contacting the surface of the target when the weapon is attached thereto, a detonator for detonating the main charge of said weapon, a spring actuated firing pin for striking said detonator, lever means releasably engaging said firing pin for normally holding said pin in a retracted position, a spring actuated shaft having a hub portion rotatably mounted thereon, said hub portion having a finger-like extension thereon normally contacting said lever means to maintain said lever means engaged with said firing pin, said hub portion further having a sharp-edged projection thereon rAdially displaced from said finger extension, a timing mechanism, and means actuated by said timer mechanism after a predetermined period of time has elapsed for releasing said spring actuated shaft whereby said shaft moves past said plunger and said sharp-edged projection becomes embedded in said plunger, whereby any subsequent movement of said plunger in either direction caused by an attempt to remove the weapon from the target will cause the plunger to rotate the hub portion and finger extension thereon to release said lever means and thereby detonate the weapon.
 3. Apparatus according to claim 2 wherein said timer mechanism actuated means includes a shutter element physically positioned between said firing pin and said detonator during the transporting and handling of the weapon and adapted to be displaced from that position when the timer mechanism is fully wound to arm the device, said shutter having an integral segment extending therefrom for releasing said spring actuated shaft at the end of the arming period.
 4. Apparatus according to claim 2 and further including means for arresting the movement of the timing mechanism if said plunger is permitted to move more than a predetermined distance when actuated to contact the surface of the target, whereby if an improper placement of the weapon is made or if the plunger is actuated accidentally during handling, the timing cycle will be prevented from being completed and the weapon will not automatically fire.
 5. An anti-removal device for a limpet weapon comprising, a spring biased plunger in said weapon for contacting the surface of the target when the weapon is attached thereto and suitably armed, a detonator for detonating the main charge of the weapon, a spring actuated firing pin for striking said detonator, and means responsive to movement in either direction of said armed plunger for releasing said firing pin to detonate the limpet weapon. 